Pil Gyu Park1, Byung-Woo Yoo1, Jason Jungsik Song2, Yong-Beom Park2, Sang-Won Lee3. 1. Division of Rheumatology, Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea. 2. Division of Rheumatology, Department of Internal Medicine and Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul, Republic of Korea. 3. Division of Rheumatology, Department of Internal Medicine and Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul, Republic of Korea. sangwonlee@yuhs.ac.